This application represents a renewal of an ongoing Program Project, focused on the use of adenovirus (Ad)-mediated gene transfer for the therapy of the respiratory manifestations of cystic fibrosis (CF). Our renewal has the unifying theme and objective that by understanding the biology of Ad vector-mediated gene transfer, and the host responses to the Ad vectors, we will make progress toward the successful use of these vectors for gene therapy for the respiratory manifestations of CF. Specifically, the projects in this application focus on: modifying capsid components of Ad vectors to use alternative routes of entry into the respiratory epithelium, circumvent humoral immunity directed against the Ad capsid, and minimize inflammation initiated by the vector; understanding the biology of the intracellular unidirectional trafficking of AD vectors, including the entry, translocation and nuclear interaction of Ad vectors in airway epithelial cells; and defining and circumventing the cellular and innate immune defenses against AD vectors: To support the 3 projects, are the cores (Vector; Molecular Analysis; Cell biology-Experimental animal). This expanded Program Project is an obvious extension of the current Program Project, reflecting ongoing scientific collaborations among the investigators in the individual projects focused on Ad vector mediated gene therapy for CF, and the major commitment of our institution to the infrastructure for Core facilities, enabling the investigators to share biologic reagents, technical expertise, laboratory facilities, and overlapping scientific interests.